feat: add Docker Compose support

- Add Dockerfile with PHP 8.3-fpm-alpine and dig command
- Add docker-compose.yml with nginx and php-fpm services
- Add nginx configuration optimized for the application
- Add entrypoint script for automatic permissions handling
- Add .dockerignore to optimize build context
- Add Makefile for convenient Docker operations
- Add comprehensive Docker documentation to README
- Add Docker troubleshooting guide

The Docker setup provides:
- Easy one-command deployment
- Automatic dig path configuration
- Proper cache directory permissions
- Development-friendly volume mounts
- Optimized Alpine-based images

Author: Lars-

.dockerignore

@@ -0,0 +1,35 @@
+# Git
+.git
+.gitignore
+
+# DDEV
+.ddev/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+error_log
+access_log
+
+# Documentation
+README.md
+LICENSE
+
+# Docker files (don't need to copy these into the image)
+docker-compose.yml
+Dockerfile
+.dockerignore
+
+# Cache (will be created by Dockerfile)
+cache/*
+!cache/.gitkeep

Dockerfile

@@ -0,0 +1,37 @@
+FROM php:8.3-fpm-alpine
+
+# Install required packages
+RUN apk add --no-cache \
+    bind-tools \
+    && docker-php-ext-install -j$(nproc) \
+    opcache
+
+# Configure PHP
+RUN { \
+    echo 'opcache.memory_consumption=128'; \
+    echo 'opcache.interned_strings_buffer=8'; \
+    echo 'opcache.max_accelerated_files=4000'; \
+    echo 'opcache.revalidate_freq=2'; \
+    echo 'opcache.fast_shutdown=1'; \
+    echo 'opcache.enable_cli=1'; \
+} > /usr/local/etc/php/conf.d/opcache-recommended.ini
+
+# Set working directory
+WORKDIR /var/www/html
+
+# Copy application files
+COPY . /var/www/html
+
+# Create cache directory with proper permissions
+RUN mkdir -p cache && \
+    chown -R www-data:www-data cache && \
+    chmod 755 cache
+
+# Copy entrypoint script
+COPY docker/entrypoint.sh /usr/local/bin/
+RUN chmod +x /usr/local/bin/entrypoint.sh
+
+EXPOSE 9000
+
+ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]
+CMD ["php-fpm"]

Makefile

@@ -0,0 +1,46 @@
+.PHONY: help build up down restart logs shell test clean
+
+# Default target
+help:
+	@echo "Available commands:"
+	@echo "  make build    - Build Docker images"
+	@echo "  make up       - Start containers"
+	@echo "  make down     - Stop containers"
+	@echo "  make restart  - Restart containers"
+	@echo "  make logs     - View logs"
+	@echo "  make shell    - Access PHP container shell"
+	@echo "  make test     - Test dig command"
+	@echo "  make clean    - Remove containers and images"
+
+# Build Docker images
+build:
+	docker compose build
+
+# Start containers
+up:
+	docker compose up -d
+	@echo "Application is running at http://localhost:8080"
+
+# Stop containers
+down:
+	docker compose down
+
+# Restart containers
+restart: down up
+
+# View logs
+logs:
+	docker compose logs -f
+
+# Access PHP container shell
+shell:
+	docker compose exec php sh
+
+# Test dig command
+test:
+	docker compose exec php dig google.com +short
+
+# Clean up everything
+clean:
+	docker compose down -v
+	docker image rm opensource-digwebinterface-php || true

README.md

@@ -57,6 +57,11 @@ A modern, secure web interface for DNS lookups using the `dig` command. Perfect
 
 ## 📋 Requirements
 
+### For Docker Installation (Recommended)
+- **Docker** 20.10 or higher
+- **Docker Compose** v2 or higher
+
+### For Manual Installation
 - **PHP 8.3** or higher with the following extensions:
   - `json` (for AJAX API)
   - `filter` (for input validation)
@@ -66,7 +71,43 @@ A modern, secure web interface for DNS lookups using the `dig` command. Perfect
 
 ## 🚀 Installation
 
-### Using DDEV (Recommended for Development)
+### Using Docker Compose (Recommended)
+
+1. **Clone the repository**:
+   ```bash
+   git clone https://github.com/yourusername/opensource-digwebinterface.git
+   cd opensource-digwebinterface
+   ```
+
+2. **Start the containers**:
+   ```bash
+   docker compose up -d
+   ```
+
+3. **Access the interface**:
+   ```
+   http://localhost:8080
+   ```
+
+4. **View logs** (optional):
+   ```bash
+   docker compose logs -f
+   ```
+
+5. **Stop the containers**:
+   ```bash
+   docker compose down
+   ```
+
+#### Docker Features
+- **PHP 8.3** with FPM for optimal performance
+- **Nginx** web server with optimized configuration
+- **Alpine Linux** base for minimal image size
+- **dig command** pre-installed and configured
+- **Volume mounts** for easy development
+- **Automatic permissions** handling for cache directory
+
+### Using DDEV (Alternative for Development)
 
 1. **Clone the repository**:
    ```bash
@@ -285,6 +326,71 @@ Add new DNS record types in `config/config.php`:
 ],
 ```
 
+## 🐳 Docker Troubleshooting
+
+### Common Issues
+
+1. **Port 8080 already in use**:
+   ```bash
+   # Change the port in docker-compose.yml
+   ports:
+     - "8081:80"  # Use port 8081 instead
+   ```
+
+2. **Permission denied errors**:
+   ```bash
+   # Rebuild with proper permissions
+   docker compose down
+   docker compose build --no-cache
+   docker compose up -d
+   ```
+
+3. **dig command not working**:
+   ```bash
+   # Test dig inside container
+   docker compose exec php dig google.com
+   
+   # Check dig path
+   docker compose exec php which dig
+   ```
+
+4. **Changes not reflecting**:
+   ```bash
+   # Restart services
+   docker compose restart
+   
+   # Or rebuild if needed
+   docker compose down
+   docker compose up -d --build
+   ```
+
+### Docker Commands Reference
+
+```bash
+# Start services
+docker compose up -d
+
+# Stop services
+docker compose down
+
+# View logs
+docker compose logs -f
+docker compose logs -f php    # PHP logs only
+docker compose logs -f nginx  # Nginx logs only
+
+# Execute commands in container
+docker compose exec php sh                    # Shell access
+docker compose exec php dig example.com       # Run dig command
+docker compose exec php php -v                # Check PHP version
+
+# Rebuild images
+docker compose build
+docker compose build --no-cache               # Force rebuild
+
+# Remove everything (including volumes)
+docker compose down -v
+```
+
 ## 🤝 Contributing
 
 Contributions are welcome! Please:

docker-compose.yml

@@ -0,0 +1,42 @@
+version: '3.8'
+
+services:
+  nginx:
+    image: nginx:alpine
+    container_name: dig-nginx
+    ports:
+      - "8080:80"
+    volumes:
+      - ./docker/nginx.conf:/etc/nginx/conf.d/default.conf:ro
+      - .:/var/www/html:ro
+    depends_on:
+      - php
+    networks:
+      - dig-network
+    restart: unless-stopped
+
+  php:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    container_name: dig-php
+    volumes:
+      - .:/var/www/html
+      - ./cache:/var/www/html/cache:rw
+    environment:
+      - PHP_FPM_PM=dynamic
+      - PHP_FPM_PM_MAX_CHILDREN=5
+      - PHP_FPM_PM_START_SERVERS=2
+      - PHP_FPM_PM_MIN_SPARE_SERVERS=1
+      - PHP_FPM_PM_MAX_SPARE_SERVERS=3
+    networks:
+      - dig-network
+    restart: unless-stopped
+    # Ensure DNS works properly in container
+    dns:
+      - 8.8.8.8
+      - 8.8.4.4
+
+networks:
+  dig-network:
+    driver: bridge

docker/build.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+# Build and run script for Docker deployment
+
+echo "Building Docker images..."
+docker compose build
+
+echo "Starting services..."
+docker compose up -d
+
+echo "Waiting for services to be ready..."
+sleep 5
+
+echo "Testing dig command in container..."
+docker compose exec php dig google.com +short
+
+echo ""
+echo "Services are running!"
+echo "Access the application at: http://localhost:8080"
+echo ""
+echo "To stop services: docker compose down"
+echo "To view logs: docker compose logs -f"

docker/entrypoint.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+set -e
+
+# Ensure cache directory exists with proper permissions
+mkdir -p /var/www/html/cache
+chown -R www-data:www-data /var/www/html/cache
+chmod 755 /var/www/html/cache
+
+# Update dig path in config if needed
+DIG_PATH=$(which dig)
+if [ -f /var/www/html/config/config.php ]; then
+    sed -i "s|'dig_path' => '[^']*'|'dig_path' => '$DIG_PATH'|g" /var/www/html/config/config.php
+fi
+
+# Execute the original command
+exec "$@"

docker/nginx.conf

@@ -0,0 +1,54 @@
+server {
+    listen 80;
+    server_name localhost;
+    root /var/www/html;
+    index index.php;
+
+    # Charset
+    charset utf-8;
+
+    # Logs
+    access_log /var/log/nginx/access.log;
+    error_log /var/log/nginx/error.log;
+
+    # Main location
+    location / {
+        try_files $uri $uri/ /index.php?$query_string;
+    }
+
+    # API location
+    location /api {
+        try_files $uri $uri/ /api/query.php?$query_string;
+    }
+
+    # PHP processing
+    location ~ \.php$ {
+        try_files $uri =404;
+        fastcgi_split_path_info ^(.+\.php)(/.+)$;
+        fastcgi_pass php:9000;
+        fastcgi_index index.php;
+        include fastcgi_params;
+        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
+        fastcgi_param PATH_INFO $fastcgi_path_info;
+        
+        # Increase timeouts for DNS queries
+        fastcgi_read_timeout 30s;
+        fastcgi_send_timeout 30s;
+    }
+
+    # Deny access to hidden files
+    location ~ /\. {
+        deny all;
+    }
+
+    # Security headers
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header X-XSS-Protection "1; mode=block" always;
+
+    # Gzip compression
+    gzip on;
+    gzip_vary on;
+    gzip_min_length 1024;
+    gzip_types text/plain text/css text/javascript application/javascript application/json;
+}